Abstract: A plastic blower impeller including an integrally formed plastic hub having three axial slots therein equidistantly located around the hub. A bore in the hub includes transverse ribs for engaging with an annular groove in the driving shaft of an electric motor. A flat surface is formed inside the bore for engaging with the corresponding flat surface on the driving shaft of an electric motor. A resilient expandable split metal sleeve engages the exterior surface of the hub.

Abstract: The present invention is a diagnosis and testing system for a temperature control system which includes a communication bus, a control processor, and a service thermostat. The communication bus is coupled to substantially all of the components of the system. The control processor initiates communication between components by sending a bus address over the bus. The control processor includes an address decoder for recognizing various bus address signals, including a normal thermostat bus address and a service thermostat bus address. The service thermostat has a switch, a processor, and a bus interface unit. The switch selects the operating mode of the service thermostat, e.g. either normal or service modes. The bus interface unit communicates over the bus for the service thermostat processor. The service thermostat processor operates the service thermostat and is adapted to communicate over the bus using a bus address according to the operating mode which is determined by the switch.

Abstract: A plastic blower including a clam shell housing. The clam shell members of the housing are sealed together by means of a groove in the edge of one of the clam shell members and a tongue formed on the edge of the other clam shell member. A strip of flexible sealing material is disposed in the groove and is compressed therein by engagement with the protruding tongue. The spaced between the tongue and the walls of the groove converges toward the open end of the groove, whereby an increase or decrease of pressure within the housing relative to the ambient pressure causes the sealing strip to be further wedged into the space, thereby increasing the effectiveness of the seal.

Abstract: A cover for an air conditioner condenser unit which is formed from a single unitary sheet of material. The cover includes a peripheral portion, a central portion, and an unbroken ring portion located intermediate the peripheral and central portions. The peripheral, central and ring portions are generally coplanar. A first set of louvres interconnects the central portion and the ring portion. A second set of louvres connects the ring portion and the peripheral portions. The angle of inclination of the louvres with respect to the plane of the cover varies over the length of the louvres.

Abstract: A hexagonal carton including four upstanding sidewall panels and two diagonally opposed corner panels. The entire carton is formed from a single blank. The corner panels include minor flaps hingedly foldably connected thereto which interact with minor flaps foldably hingedly connected to the adjoining sidewall panels to form a rigid interlocked cover panel which withstands lateral pressures exerted on the sidewall panels of the carton. Major flaps are foldably hingedly connected to two of the sidewall panels to form a cover panel to cover the interlocking minor flaps.

Abstract: An improved power vent and associated control system for a heating apparatus such as a furnace. The invention utilizes a vent blower and a flow control orifice device permitting the use of a single size air moving device and motor with different size furnaces. The control is arranged to discontinue delivery of fuel to the furnace in the event of a blockage of the furnace flue or a failure of the air moving structure. In one form of the invention, a pressure condition is sensed downstream of the air moving structure to detect the failure conditions. In another form of the invention, the control utilizes structure to sense the speed of the air moving device. The invention comprehends the use of a motor for driving the air moving device which varies in speed substantially between the unloaded and loaded conditions. The air moving device preferably unloads under high discharge pressure conditions, such as by a blocked flue.

Abstract: In the operation of a heat pipe furnace having a plurality of heat pipes and means for conducting a heated fluid in sequential heat transfer association with the heat pipes, an apparatus and method of detecting a malfunction of any one of the heat pipes of said plurality comprising means for and the steps of monitoring the temperature of the most sequentially downstream heat pipe of the plurality of heat pipes and determining whether said monitored temperature is within a preselected range of temperatures.

Abstract: An improved fin configuration is provided for use in central air conditioning unit heat exchangers in which heat transfer takes place between a first fluid, typically a refrigerant, flowing inside a nested plurality of tubes and a second fluid, typically air, flowing between the tubes and through a plurality of heat conducting fins attached to and arrayed between the tubes. Lanced pairs of streamwise adjacent bridge-like formations, one out each side of a generally corrugated fin surface, provide numerous leading edges to generate a plurality of reforming velocity and heat transfer boundary layers which leads to an increase in flow turbulence for enhanced heat transfer between the fins and the second fluid. By strategic location of a pair of such formations between tubes, with the upstream one of the pair at a positive angle of attack to the flow, air flow is directed through the fin to mix with flow on the other side of the fin and hence the heat transfer rate is improved.

Abstract: A safety device for monitoring the condition of the condensate outlet conduit in a high efficiency furnace is provided which comprises a float member positioned in a condensate trap arranged to float on the condensate and to rise in response to a rising level of condensate in the trap to block the gas vent inlet. A pressure sensing device is utilized to sense the back pressure in the vent and when the float blocks the vent inlet, the back pressure increased and the sensing device will then operate to terminate operation of the furnace.

Abstract: A metal insert is provided for reducing NO.sub.x emissions in a gas burner which comprises an inverted channel member having support legs movably retained in at least one of the burner ports to allow for movement caused by thermal expansion and contraction of the channel member. The channel member has downwardly extending leg portions positioned adjacent a high temperature zone of the gas flame and within a low temperature zone of the flame.

Abstract: A heat pipe heat transfer structure for use in a furnace wherein individual heat pipes are arranged in a series for successive heat transfer association with the hot products of combustion of the furnace. The heat transfer enclosure defines successively a combustion chamber portion, an acoustic decoupling portion, and an input heat transfer chamber portion. The heat transfer chamber portion, in turn, is divided into first and second portions. The first portion of the input heat transfer chamber portion, in the illustrated embodiment, decreases in cross sectional area in a direction away from the burner. The final portion of the input heat transfer chamber portion, in the illustrated embodiment, has a constant cross sectional area.

Abstract: An improved condensate neutralizer for use in a high efficiency furnace utilizing hydrocarbon gaseous fuel wherein acidic liquid condensate forms. The neutralizer is provided with a bypass for conducting the condensate from the furnace directly to a drain without passing through the neutralizer in the event condensate flow through the neutralizer becomes substantially impeded. Also disclosed is structure for indicating substantial impediment of flow of the condensate through the neutralizer for alerting the user to the need of servicing of the neutralizer. A separator/trap is provided for transferring the condensate from the furnace selectively to the neutralizer or bypass.

Abstract: A domestic forced-air furnace provided with a condensate collector downstream of air moving structure for flowing the products of combustion through the furnace. The furnace includes a secondary heat exchanger. Condensate produced therein is transferred therefrom through the air moving structure to the condensate separator. The secondary heat exchanger and air moving structure are inclined slightly to the horizontal so as to cause continuous flow of condensate therethrough not only during operation of the furnace but also subsequent thereto to assure removal of condensate from the furnace components and thereby avoid corrosive damage thereto from the condensate. The secondary heat exchanger provides the primary pressure drop in the combustion product flow path, permitting control of the furnace capacity by simple modification thereof without the need for changing other components, such as the air moving structure.

Abstract: An improved power vent and associated control system for a heating apparatus such as a furnace. The invention utilizes a vent blower and a flow control orifice device permitting the use of a single size air moving device and motor with different size furnaces. The control is arranged to discontinue delivery of fuel to the furnace in the event of a blockage of the furnace flue or a failure of the air moving structure. In one form of the invention, a pressure condition is sensed downstream of the air moving structure to detect the failure conditions. In another form of the invention, the control utilizes structure to sense the speed of the air moving device. The invention comprehends the use of a motor for driving the air moving device which varies in speed substantially between the unloaded and loaded conditions. The air moving device preferably unloads under high discharge pressure conditions, such as by a blocked flue.

Abstract: A terminal block and capacitor mount for use in an apparatus, such as a blower, having a drive motor. The terminal block is arranged to provide connections to the windings of the motor and to a capacitor secured to the terminal block. The assembly is arranged to be mounted to a support wall associated with the blower. Terminals are exposed through opposite faces of the housing of the assembly. The housing is secured to the support wall with one face exposed through the support wall opening to permit connection to the terminals therethrough. In the illustrated embodiment, the terminals to which the motor supply leads and power supply leads are connected are exposed through the support wall opening. Grounding straps are provided for grounding the capacitor case to the support wall as a result of the mounting of the capacitor to the assembly.

Abstract: A high efficiency domestic furnace incorporates means for separating and neutralizing flue gas condensate. Acidic condensate from the flue gas products of combustion is neutralized by contact with neutralizing material in a housing through which the condensate is flowed. The use of the neutralizer in connection with a high efficiency domestic furnace permits discharge of the condensate directly to the household drain. The neutralizer is arranged to be self-flushing and defines a serpentine, series flow path and is arranged to discharge the neutralized condensate as a result of the entry of additional acidic condensate at its inlet. To enhance the operation of the neutralizer, it is arranged to be vibrated during normal operation of the furnace.

Abstract: A high efficiency domestic furnace incorporates means for separating and neutralizing flue gas condensate. Acidic condensate from the flue gas products of combustion is neutralized by contact with neutralizing material in a housing through which the condensate is flowed. The use of the neutralizer in connection with a high efficiency domestic furnace permits discharge of the condensate directly to the household drain. The neutralizer is arranged to be self-flushing and defines a serpentine, series flow path and is arranged to discharge the neutralized condensate as a result of the entry of additional acidic condensate at its inlet.

Abstract: A ventilation fan which is adapted to be ceiling mounted such as in an attic space above a room ceiling. The fan is arranged to pass upwardly through the space between the ceiling joists in a compact arrangement and to be extended once it is disposed above the room ceiling to define an operating configuration. In the operating configuration, the air moving apparatus is swung outwardly from the housing of the fan on a pivotally mounted wall portion thereof. The fan redirects the upwardly flowing air from the subjacent room at a substantial angle to the vertical in the attic space for improved ventilation functioning.

Abstract: A fluid flow device having a biased closure structure for selectively closing an opening in a flow conducting structure. The closure includes a pair of closure members pivoted relative to a transverse axis of the opening and biased to the closed position by a spring which is maintained spaced from the closure members in the closed position thereof. The spring has a midportion which is brought into engagement with the closure members as an incident of the movement thereof to and beyond a preselected position intermediate the closed and fully opened positions of the closure members. The spring acts to resiliently bias the closure members toward the closed position as result of the spring tension between the closed position and the intermediate position and the abutment of the midportion of the spring with the closure members at and beyond the intermediate position permits the closure members to be swung toward the fully open position with a decreased force.

Abstract: A control system for a central air conditioner. The air conditioner includes an outdoor condensing unit including a refrigerant compressor, an indoor evaporator unit, an indoor thermostat responsive to the indoor temperature for controlling the air conditioner, and a control system for protecting the air conditioner and indicating to the user certain malfunctions in the air conditioner should they occur. The malfunction indication may be by means of signal lights and a manually operable reset control is provided permitting the user to reset the control system. The malfunction indicator and reset control are disposed adjacent the thermostat for facilitated determination of the system operating condition. The control system includes an improved control portion for starting of the compressor motor which is arranged to prevent operation of the system in the event of a low power supply voltage condition.